Six hectares of evergreen forest
of Highwavy
Mountains, Western Ghats, Theni District, Tamil Nadu, India,
was censused for the damaged trees ( 30cm
girth at breast height). Among 57 damaged trees 28.07% was uprooted and
71.93% was standing broken stems. Among standing broken stems only 39.02% was
resprouted. The percentage of resprouting
of our study site was slightly higher than other forests. The resprouting and the production of multishoots
from the stumps were mainly seen in the pioneer species and resprouting was rare in the climax species. This was
contrast to other forests.

The death of the whole tree affects nutrient cycling, regeneration, and
species richness in the particular area. Tree falls are determined by local climatic
factors, physical characteristics of the substrate, and biological attributes
of trees (Brokaw 1982, Putz & Milton 1982, Putz et al. 1983, Denslow 1987,
Putz & Brokaw 1989). When a whole tree falls to
the forest floor, it; cause pulses of organic material and nutrients that can
subsequently become available to terrestrially rooted plants (Denslow 1987); increase the biomass of the forest floor,
thus creating additional habitats for terrestrial organisms. Crush seedlings,
saplings and understory plants (Aide 1987; Gartner
1989; Kinsman 1990); and affect microclimate of the ensuing gap that may
daunt or smooth the progress of seed germination of some species (Putz & Milton 1982, Brandani
et al. 1988, Swaine et al. 1990).

While many damaged trees die, some
continue to live by producing new shoots from above or below ground parts.
Most of the research has centered on regeneration from seeds, seedlings, or clonal growth (Clark & Clark 1989, Eriksson & Ehrlen 1992). Resprouting from
standing broken stems might replace the lost canopy and affect the form and
duration of gap regeneration faster than regeneration from seedlings. The
ability to resprout might allow a species to
maintain its frequency in the population (Knight 1975, Putz
& Brokaw 1989, Whigham et al. 1991).

The rates and frequency of tree
damage expected to be greater in higher elevation forests because of steeper
slopes, less stable soil and exposure to more wind. Plant adaptations to
these environmental characteristics might also be expected in wet evergreen
forest.

In this paper, we describe the
damage of the trees and report the frequency of resprouting
of snapped trees of evergreen forest
of Highwavy
Mountains, Western Ghats, Theni District, Tamil Nadu, India.

METHODS

Study Site

Our study site is situated in the Pachakumachi hill (9° 35’ to 9° 45’ N latitude and 77º
15’ to 77º 27’E longitude) of Western Ghats,
South India. The Pachakumachi
hill is surrounded by Palani Hills in the North, Sethur and Sivagiri hills in
the South, Cardamom hills and Kerala state in the
West, the Varushanadu hills in the Northeast and Thekkadi hills in the Southwest. Vaigai
and Surliyaru are the main rivers originating from Pachakumachi hill ranges.

Climate and
Soil

Climatological
data of the study site are collected from Pachakumachi
estate Climatological station. Pachakumachi
hill receives 2726 mm rainfall annually. June is recorded as the hottest
month with maximum temperature of 31°C and January is the coldest month with
the minimum temperature of 17° C. Humidity is high (95%) during the months of
June, July and August; and low humidity is noted only in the month of March
(85%). Climatological data of Pachakumachi
hill is given in Fig 1.

Pachakumachi hill has red, sandy clayey and loamy type of
soil. Physio- chemical characteristics of soil of
the study site are given in table 1.

Vegetation

In the 10,000 Acres of total area
of Pachakumachi hill, 2,000 acres are under the
cultivation of cash crops such as cardamom, coffee and tea. These plantations
are intermingled with the patches of Evergreen forests. The altitude of the
hill ranges from 600 m to 2,000 m. The vegetation ranges from scrub jungles
in the foothill to evergreen and sholas at hill
tops. Our study site is situated at an altitude of 1,700 m. Our study site is
defined as the tropical evergreen forest.

Field Work

Between June 2006 and February
2007, we censused the entire site (6 hectares) for
snapped or fallen trees and resprouting of the
standing broken stems during study period. We made frequent visits to the
study site. The damaged trees with GBH 30 cm were noted. Tree damage
was divided into three categories; a: uproot- fallen trees with exposed root
balls; b: knockdown- a broken or uprooted, tree falling as a result of a
neighboring tree hitting it; c: standing dead- tree dead, but stem not broken
or uprooted;.

During study period, all standing broken stems were checked for the
evidence of resprouting of leaves anywhere on the
stem. Standing broken stem with newly sprouted leaves were recorded as living
ones and those with no sprouting of leaves were recorded as dead ones.

The resprouted stumps were classified into
two groups; by the formation of new shoots; 1: Multishooted
stumps- The stump producing more than one new shoots; 2: Monoshooted
stumps- The stump producing only one new shoots; for this the standing broken
stumps with DBH 30 cm were tagged.

The stumps which were produced the shoots more than two in numbers,
also noted. The stumps with DBH 30 cm were noted.

RESULTS

In 6 ha study plot, 57 trees
were severely damaged. The number of damaged trees per hectare was 9.5 trees.
Among these, 28.07% were uprooted, 7.01% were standing dead, and remaining
was knocked down (Fig 1.).

All the trees that were damaged or
died during our study period (57) were identified up to species level. They
were belonging to ten families, represented by ten genera, and ten species.
The percentage of damage was seen in both cases i.e., in climax and in
pioneer species.

The uprooting of whole trees
mainly occurred in the climax species (20). All the members’ of pioneer
species were standing broken stems. The standing dead trees were the climax
species.

Resprouting of damaged trees:

The resprouting mechanism is mainly seen in the pioneer
species. Among the climax species only 4 species were resprouted.
The percent of resprouted and not resprouted standing stems was shown in the Fig 2. Other 5
species didn’t resprouted. They were considered as
the standing dead trees.

The resprouting
mechanism is mainly seen in the pioneer species. Among the climax species
only 4 species were resprouted. The percent of resprouted and not resprouted
standing stems was shown in the Fig 2. Other 5 species didn’t resprouted. They were considered as the standing dead
trees.

Euphorbiaceae
family showed 50% of resprouting among total
percentage of resprouting. Resprouting
percentage for other families were 6.25, 12.5, 12.5, and 18.75 of Guttiferae, Anacardiaceae, Elaeocarpaceae and Rutaceae
respectively. Polypetalae and Monochlymadeae
shared the percentage of resprouting (Fig 3).

The production of multi shoots was
seen only in the pioneer species. It was not seen in the climax species.
Among 8 of the resprouting pioneer species, 2 only
producing more than 2 new shoots from the standing broken stem.

DISCUSSION

The rate of resprouting in our study site was coinciding with other
forests. There was a trend that, in the mature forests, gap-colonizing
species suffer higher nonresprouting rates than other
taxa. But our result was controversy to the above
trend, i.e., in our study site the pioneer species showed the higher resprouting rate. Among the climax species only 4 species
showed the resprouting.

Likewise the resprouting,
the production of multishoots was seen only in the
gap-colonizing species. No other standing broken stems belonging to the
climax species was producing the multishoots.

ACKNOWLEDGEMENTS

We thank UGC for their financial support of this project. We also thank
Selvam for his help during the field study. Our
sincere thank to Tamil Nadu Forest Department for
their permission.